1. Field of the Invention
The present invention relates to an AV player chip and related AV system capable of sharing digital-to-analog converters, and more particularly, to an AV player chip and related AV system utilizing a multiplexer to select a signal format of the output signals.
2. Description of the Prior Art
With speedy development in information and recent advancements in multimedia technology, miscellaneous audio-video apparatuses are used for providing data transmission and sense enjoyment of images and voices. However, as the audio-video technology changes with each passing day, image signals and voice signals with multifarious signal standards come with the tide of fashion. Digital televisions usually support various analog display interfaces, for example, video signals are divided into a composite video broadcast signal (CVBS), a S video signal, a chrominance video signal (Y, Pb, or Pr), etc. TFT LCD monitors usually support image signals such as R, G, and B formats. In order to satisfy with both an externally connected television or a built in TFT LCD monitor for watching images at the same time, an AV player chip usually includes two sets of digital-to-analog converters, whereof one set of digital-to-analog converters is used for outputting an image signal in the composite video format and the S video format (or in the Y, Pb, Pr formats) to the AV terminals of the externally connected television, and the other set of digital-to-analog converters is used for outputting an image signal in the R, G, and B formats to the built in TFT LCD monitor for playing images.
Multimedia electronic products nowadays provide more and more functions due to advancements in multimedia technology and in digital storage technology. Recently, the multimedia electronic products become a large part of people's lives. Due to the multimedia electronic products such as mobile phones, portable media players, digital televisions, and other wireless device becoming mature day by day, the AV player chip of the multimedia electronic products plays a decisive role in order to make these devices possess more diverse functions. Digital-to-analog converters are usually used in the multimedia electronic products such as DVD players, VCD players, portable AV players, digital televisions, and home AV products, and users can transform image signals into an analog format to play images through the digital-to-analog converters.
Please refer to FIG. 1. FIG. 1 is a diagram of an AV player chip 10 according to the prior art. The AV player chip 10 includes a memory 11, an image decoder 12, a scaler 16, a TV encoder 14, a timing controller 18, a first set of digital-to-analog converters 15, and a second set of digital-to-analog converters 17. The first set of digital-to-analog converters 15 includes three digital-to-analog converters DAC1, and the second set of digital-to-analog converters 17 includes three digital-to-analog converters DAC2. The memory 11 is used for storing an image data and can be a static random access memory (SRAM). The image decoder 12 is coupled to an output end of the memory 11 for decoding the image data to generate a first image signal. The scaler 16 is coupled between the image decoder 12 and the timing controller 18 for adjusting the first image signal to generate a second image signal. The TV encoder 14 includes an input end 142 coupled to an output end 122 of the image decoder 12, and three output ends 144, 146, and 148, which are coupled to the three digital-to-analog converters DAC 1 of the first set of digital-to-analog converters 15 individually. The TV encoder 14 is used for transforming the first image signal into a TV video signal set. The three digital-to-analog converters DAC 1 of the first set of digital-to-analog converters 15 are used for transforming the TV video signal set outputted by the TV encoder 14 into the analog format and outputting a CVBS signal, a Y signal, and a C signal individually. The timing controller 18 includes an input end 182 coupled to an output end 162 of the scaler 16 for receiving the second image signal, and three output ends 184, 186, and 188, which are coupled to the three digital-to-analog converters DAC2 of the second set of digital-to-analog converters 17 individually. The timing controller 18 is used for generating a corresponding output signal set according to the second image signal. The three digital-to-analog converters DAC2 of the second set of digital-to-analog converters 17 are used for transforming the output signal set outputted by the timing controller 18 into the analog format and outputting a R signal, a G signal, and a B signal individually. The image decoder 12 can be an MPEG 2 decoder.
In the prior art, an AV player chip usually includes two sets of digital-to-analog converters, whereof one set of digital-to-analog converters is used for outputting an image signal in the composite video format and the S video format (or in the Y, Pb, Pr formats) to the AV terminals of the externally connected television, and the other set of digital-to-analog converters is used for outputting an image signal in the R, G, and B formats to the built in TFT LCD monitor for playing images directly. The above-mentioned method of utilizing two sets of digital-to-analog converters to transform signals is not economical. Besides, the digital-to-analog converter occupies quite large areas and wastes cost itself. As a result, chip sizes and manufacturing costs will be raised substantially.